Location: Hill 705
Date & time: Thursday, 08 November 2018 at 2:00PM - 3:00PM
Abstract: We take as starting point the assumption that a system at a mesoscopic scale is described by a set of fluctuating fields that evolves by a Langevin equation. We study general properties of the system's stationary state at the small noise limit. We argue that the system is at equilibrium when it is macroscopic reversible, that is when the most probable path to create a fluctuation from the stationary state is equal to the time reversed path that relaxes it. When this doesn't occur the system is in a nonequilibrium stationary state whose quasi-potential may present some lack of differentiability. We also derive closed equations for the two-body correlations at the stationary state and we apply them to some typical cases. Finally we obtain generalized Green-Kubo class of formulas by using the Large Deviation Principle.